The following relates generally to wireless communication, and more specifically to a directional listen before talk scheme.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system, or a New Radio (NR) system). A wireless multiple-access communications system may include a number of base stations or access network nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Wireless communication systems may operate in millimeter wave (mmW) frequency ranges, e.g., 28 GHz, 40 GHz, 60 GHz, etc. Wireless communications at mmW frequencies may be associated with increased signal attenuation (e.g., path loss), which may be influenced by various factors, such as temperature, barometric pressure, diffraction, etc. As a result, signal processing techniques, such as beamforming, may be used to coherently combine energy and overcome the path losses at mmW frequencies. Wireless communications between two wireless nodes, e.g., between a base station and a UE, may use beams or beamformed signals for transmission and/or reception.
Due to various limitations, e.g., limited number of communication chains, limited number of antennas, subarrays, etc., wireless devices cannot monitor channels in all directions at the same time. This creates a situation where the wireless device (e.g., base station, UE, etc.) determines which direction to monitor, how long to monitor any given direction, and the like. Additional concerns include, but are not limited to, which signals are exchanged between wireless devices for a given transmission and how to respond when the direction is determined busy or occupied.